imgconvert.c

现在关于h.264的源码很多

        case PIX_FMT_YUV422:
        case PIX_FMT_UYVY422:
        case PIX_FMT_RGB565:
        case PIX_FMT_RGB555:
            bits = 16;
            break;
        case PIX_FMT_UYVY411:
            bits = 12;
            break;
        default:
            bits = pf->depth * pf->nb_channels;
            break;
        }
        break;
    case FF_PIXEL_PLANAR:
        if (pf->x_chroma_shift == 0 && pf->y_chroma_shift == 0) {
            bits = pf->depth * pf->nb_channels;
        } else {
            bits = pf->depth + ((2 * pf->depth) >>
                                (pf->x_chroma_shift + pf->y_chroma_shift));
        }
        break;
    case FF_PIXEL_PALETTE:
        bits = 8;
        break;
    default:
        bits = -1;
        break;
    }
    return bits;
}

static int avcodec_find_best_pix_fmt1(int pix_fmt_mask,
                                      int src_pix_fmt,
                                      int has_alpha,
                                      int loss_mask)
{
    int dist, i, loss, min_dist, dst_pix_fmt;

    /* find exact color match with smallest size */
    dst_pix_fmt = -1;
    min_dist = 0x7fffffff;
    for(i = 0;i < PIX_FMT_NB; i++) {
        if (pix_fmt_mask & (1 << i)) {
            loss = avcodec_get_pix_fmt_loss(i, src_pix_fmt, has_alpha) & loss_mask;
            if (loss == 0) {
                dist = avg_bits_per_pixel(i);
                if (dist < min_dist) {
                    min_dist = dist;
                    dst_pix_fmt = i;
                }
            }
        }
    }
    return dst_pix_fmt;
}

/**
 * find best pixel format to convert to. Return -1 if none found
 */
int avcodec_find_best_pix_fmt(int pix_fmt_mask, int src_pix_fmt,
                              int has_alpha, int *loss_ptr)
{
    int dst_pix_fmt, loss_mask, i;
    static const int loss_mask_order[] = {
        ~0, /* no loss first */
        ~FF_LOSS_ALPHA,
        ~FF_LOSS_RESOLUTION,
        ~(FF_LOSS_COLORSPACE | FF_LOSS_RESOLUTION),
        ~FF_LOSS_COLORQUANT,
        ~FF_LOSS_DEPTH,
        0,
    };

    /* try with successive loss */
    i = 0;
    for(;;) {
        loss_mask = loss_mask_order[i++];
        dst_pix_fmt = avcodec_find_best_pix_fmt1(pix_fmt_mask, src_pix_fmt,
                                                 has_alpha, loss_mask);
        if (dst_pix_fmt >= 0)
            goto found;
        if (loss_mask == 0)
            break;
    }
    return -1;
 found:
    if (loss_ptr)
        *loss_ptr = avcodec_get_pix_fmt_loss(dst_pix_fmt, src_pix_fmt, has_alpha);
    return dst_pix_fmt;
}

void ff_img_copy_plane(uint8_t *dst, int dst_wrap,
                           const uint8_t *src, int src_wrap,
                           int width, int height)
{
    if((!dst) || (!src))
        return;
    for(;height > 0; height--) {
        memcpy(dst, src, width);
        dst += dst_wrap;
        src += src_wrap;
    }
}

/**
 * Copy image 'src' to 'dst'.
 */
void img_copy(AVPicture *dst, const AVPicture *src,
              int pix_fmt, int width, int height)
{
    int bwidth, bits, i;
    PixFmtInfo *pf = &pix_fmt_info[pix_fmt];

    pf = &pix_fmt_info[pix_fmt];
    switch(pf->pixel_type) {
    case FF_PIXEL_PACKED:
        switch(pix_fmt) {
        case PIX_FMT_YUV422:
        case PIX_FMT_UYVY422:
        case PIX_FMT_RGB565:
        case PIX_FMT_RGB555:
            bits = 16;
            break;
        case PIX_FMT_UYVY411:
            bits = 12;
            break;
        default:
            bits = pf->depth * pf->nb_channels;
            break;
        }
        bwidth = (width * bits + 7) >> 3;
        ff_img_copy_plane(dst->data[0], dst->linesize[0],
                       src->data[0], src->linesize[0],
                       bwidth, height);
        break;
    case FF_PIXEL_PLANAR:
        for(i = 0; i < pf->nb_channels; i++) {
            int w, h;
            w = width;
            h = height;
            if (i == 1 || i == 2) {
                w >>= pf->x_chroma_shift;
                h >>= pf->y_chroma_shift;
            }
            bwidth = (w * pf->depth + 7) >> 3;
            ff_img_copy_plane(dst->data[i], dst->linesize[i],
                           src->data[i], src->linesize[i],
                           bwidth, h);
        }
        break;
    case FF_PIXEL_PALETTE:
        ff_img_copy_plane(dst->data[0], dst->linesize[0],
                       src->data[0], src->linesize[0],
                       width, height);
        /* copy the palette */
        ff_img_copy_plane(dst->data[1], dst->linesize[1],
                       src->data[1], src->linesize[1],
                       4, 256);
        break;
    }
}

/* XXX: totally non optimized */

static void yuv422_to_yuv420p(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    const uint8_t *p, *p1;
    uint8_t *lum, *cr, *cb, *lum1, *cr1, *cb1;
    int w;

    p1 = src->data[0];
    lum1 = dst->data[0];
    cb1 = dst->data[1];
    cr1 = dst->data[2];

    for(;height >= 1; height -= 2) {
        p = p1;
        lum = lum1;
        cb = cb1;
        cr = cr1;
        for(w = width; w >= 2; w -= 2) {
            lum[0] = p[0];
            cb[0] = p[1];
            lum[1] = p[2];
            cr[0] = p[3];
            p += 4;
            lum += 2;
            cb++;
            cr++;
        }
        if (w) {
            lum[0] = p[0];
            cb[0] = p[1];
            cr[0] = p[3];
            cb++;
            cr++;
        }
        p1 += src->linesize[0];
        lum1 += dst->linesize[0];
        if (height>1) {
            p = p1;
            lum = lum1;
            for(w = width; w >= 2; w -= 2) {
                lum[0] = p[0];
                lum[1] = p[2];
                p += 4;
                lum += 2;
            }
            if (w) {
                lum[0] = p[0];
            }
            p1 += src->linesize[0];
            lum1 += dst->linesize[0];
        }
        cb1 += dst->linesize[1];
        cr1 += dst->linesize[2];
    }
}

static void uyvy422_to_yuv420p(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    const uint8_t *p, *p1;
    uint8_t *lum, *cr, *cb, *lum1, *cr1, *cb1;
    int w;

    p1 = src->data[0];

    lum1 = dst->data[0];
    cb1 = dst->data[1];
    cr1 = dst->data[2];

    for(;height >= 1; height -= 2) {
        p = p1;
        lum = lum1;
        cb = cb1;
        cr = cr1;
        for(w = width; w >= 2; w -= 2) {
            lum[0] = p[1];
            cb[0] = p[0];
            lum[1] = p[3];
            cr[0] = p[2];
            p += 4;
            lum += 2;
            cb++;
            cr++;
        }
        if (w) {
            lum[0] = p[1];
            cb[0] = p[0];
            cr[0] = p[2];
            cb++;
            cr++;
        }
        p1 += src->linesize[0];
        lum1 += dst->linesize[0];
        if (height>1) {
            p = p1;
            lum = lum1;
            for(w = width; w >= 2; w -= 2) {
                lum[0] = p[1];
                lum[1] = p[3];
                p += 4;
                lum += 2;
            }
            if (w) {
                lum[0] = p[1];
            }
            p1 += src->linesize[0];
            lum1 += dst->linesize[0];
        }
        cb1 += dst->linesize[1];
        cr1 += dst->linesize[2];
    }
}


static void uyvy422_to_yuv422p(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    const uint8_t *p, *p1;
    uint8_t *lum, *cr, *cb, *lum1, *cr1, *cb1;
    int w;

    p1 = src->data[0];
    lum1 = dst->data[0];
    cb1 = dst->data[1];
    cr1 = dst->data[2];
    for(;height > 0; height--) {
        p = p1;
        lum = lum1;
        cb = cb1;
        cr = cr1;
        for(w = width; w >= 2; w -= 2) {
            lum[0] = p[1];
            cb[0] = p[0];
            lum[1] = p[3];
            cr[0] = p[2];
            p += 4;
            lum += 2;
            cb++;
            cr++;
        }
        p1 += src->linesize[0];
        lum1 += dst->linesize[0];
        cb1 += dst->linesize[1];
        cr1 += dst->linesize[2];
    }
}


static void yuv422_to_yuv422p(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    const uint8_t *p, *p1;
    uint8_t *lum, *cr, *cb, *lum1, *cr1, *cb1;
    int w;

    p1 = src->data[0];
    lum1 = dst->data[0];
    cb1 = dst->data[1];
    cr1 = dst->data[2];
    for(;height > 0; height--) {
        p = p1;
        lum = lum1;
        cb = cb1;
        cr = cr1;
        for(w = width; w >= 2; w -= 2) {
            lum[0] = p[0];
            cb[0] = p[1];
            lum[1] = p[2];
            cr[0] = p[3];
            p += 4;
            lum += 2;
            cb++;
            cr++;
        }
        p1 += src->linesize[0];
        lum1 += dst->linesize[0];
        cb1 += dst->linesize[1];
        cr1 += dst->linesize[2];
    }
}

static void yuv422p_to_yuv422(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    uint8_t *p, *p1;
    const uint8_t *lum, *cr, *cb, *lum1, *cr1, *cb1;
    int w;

    p1 = dst->data[0];
    lum1 = src->data[0];
    cb1 = src->data[1];
    cr1 = src->data[2];
    for(;height > 0; height--) {
        p = p1;
        lum = lum1;
        cb = cb1;
        cr = cr1;
        for(w = width; w >= 2; w -= 2) {
            p[0] = lum[0];
            p[1] = cb[0];
            p[2] = lum[1];
            p[3] = cr[0];
            p += 4;
            lum += 2;
            cb++;
            cr++;
        }
        p1 += dst->linesize[0];
        lum1 += src->linesize[0];
        cb1 += src->linesize[1];
        cr1 += src->linesize[2];
    }
}

static void yuv422p_to_uyvy422(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    uint8_t *p, *p1;
    const uint8_t *lum, *cr, *cb, *lum1, *cr1, *cb1;
    int w;

    p1 = dst->data[0];
    lum1 = src->data[0];
    cb1 = src->data[1];
    cr1 = src->data[2];
    for(;height > 0; height--) {
        p = p1;
        lum = lum1;
        cb = cb1;
        cr = cr1;
        for(w = width; w >= 2; w -= 2) {
            p[1] = lum[0];
            p[0] = cb[0];
            p[3] = lum[1];
            p[2] = cr[0];
            p += 4;
            lum += 2;
            cb++;
            cr++;
        }
        p1 += dst->linesize[0];
        lum1 += src->linesize[0];
        cb1 += src->linesize[1];
        cr1 += src->linesize[2];
    }
}

static void uyvy411_to_yuv411p(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    const uint8_t *p, *p1;
    uint8_t *lum, *cr, *cb, *lum1, *cr1, *cb1;
    int w;

    p1 = src->data[0];
    lum1 = dst->data[0];
    cb1 = dst->data[1];
    cr1 = dst->data[2];
    for(;height > 0; height--) {
        p = p1;
        lum = lum1;
        cb = cb1;
        cr = cr1;
        for(w = width; w >= 4; w -= 4) {
            cb[0] = p[0];
            lum[0] = p[1];
            lum[1] = p[2];
            cr[0] = p[3];
            lum[2] = p[4];
            lum[3] = p[5];
            p += 6;
            lum += 4;
            cb++;
            cr++;
        }
        p1 += src->linesize[0];
        lum1 += dst->linesize[0];
        cb1 += dst->linesize[1];
        cr1 += dst->linesize[2];
    }
}


static void yuv420p_to_yuv422(AVPicture *dst, const AVPicture *src,
                              int width, int height)
{
    int w, h;
    uint8_t *line1, *line2, *linesrc = dst->data[0];
    uint8_t *lum1, *lum2, *lumsrc = src->data[0];
    uint8_t *cb1, *cb2 = src->data[1];
    uint8_t *cr1, *cr2 = src->data[2];

    for(h = height / 2; h--;) {
        line1 = linesrc;
        line2 = linesrc + dst->linesize[0];

        lum1 = lumsrc;
        lum2 = lumsrc + src->linesize[0];

        cb1 = cb2;
        cr1 = cr2;

        for(w = width / 2; w--;) {
                *line1++ = *lum1++; *line2++ = *lum2++;
                *line1++ =          *line2++ = *cb1++;
                *line1++ = *lum1++; *line2++ = *lum2++;
                *line1++ =          *line2++ = *cr1++;
        }

        linesrc += dst->linesize[0] * 2;
        lumsrc += src->linesize[0] * 2;
        cb2 += src->linesize[1];
        cr2 += src->linesize[2];
    }
}

static void yuv420p_to_uyvy422(AVPicture *dst, const AVPicture *src,